Mark Lenard

Admiral Kirk and his bridge crew risk their careers stealing the decommissioned Enterprise to return to the restricted Genesis planet to recover Spock's body (imdb)

Two astronauts travelling across the simian-dominated world with their chimpanzee friend are captured and forced to fight in a gladiatorial arena. Later, they search the ruins of an ancient city for clues to the fate of the human race.

To avoid losing their logging crew, the Bolt brothers bring 100 prospective brides from Massachusetts to Seattle, using money borrowed from sawmill owner Stempel. Should one of the girls decide to go home, or should they fail to meet Stempel's timber quotas, they will still lose their mountain to him.

First follow-up film to the series is 2 episodes back-to-back. In Escape from Tomorrow (1974), the astronauts crashland in their own future, which they discover to be ape-ruled, and they and Galen become fugitives after being tricked into escaping by the ruthless Urko. In The Trap (1974), Urko and Burke are trapped in an underground metro station in the ruins of a city, and must cooperate in order to escape, while Urko learns some uncomfortable truths about humans and Earth's past.

To save Earth from an alien probe, Kirk and his crew go back in time to retrieve the only beings who can communicate with it, humpback whales (imdb)

When a destructive space entity is spotted approaching Earth, Admiral Kirk resumes command of the Starship Enterprise in order to intercept, examine, and hopefully stop it (imdb)